Step 11: Apply Velcro To One Side Of Switch For Mounting

Step 12: Test Your CD Switch

Test your new CD switch by plugging it into a switch adapted toy or device (anything controlled by a 3.5mm switch jack) and pressing the two CDs toge...

In the realm of assistive technology, a switch (aka "ability switch") can be anything from a plastic button to a muscle twitch sensor. This album is a great look at the variety of switches that are available. These switches are almost always wired to a 3.5mm (1/8") mono plug, and can be connected to anything with a matching jack. They are used with power wheelchairs, computers, speech devices, toys, remote controls, and so on.

The problem is that switches are expensive. A basic Jellybean Switch or Buddy Button costs around $50-60 (USD), for just a plastic button. While these are worth their weight in gold, the price is still a bit steep, especially in the low-budget/non-profit world of assistive technology.

Sometimes, it's handy to make your own.

Fortunately, a switch is a very simple thing. It's just a circuit closing, just two wires touching. We will use less than $10 (USD) worth of parts to let a person press a surface (in this case a CD), and touch two wires together. R. J. Cooper also sells CD Switch Kits for about $10 (USD) each, in packs of five or ten.

Save the left over scraps from this project, as you can use them to build a No-Solder Battery Interrupter, which you can use to let this switch control toys and other devices.

then if it wears out make more they are cheap. you could even take some finer stranded wire and place between cd and foil then press foil on then add the velcro and wire as shown for more areas of contact.

Heck I swear my brain was in neutral when I wrote that use a disposable pie plate again put wire under the plate as the wires held down by the velcro, and slice them.

If you put say two perforations in the pie cut outs you can "weave the wire through then apply to the cd and the velcro ill make the top stick very nicely while the 3m stuff will keep the underside in place. contact will be longer and spread out.

do not waste time making circles put the cd and plate toghter press down , use tubber roller if you have one , then trim excess off the discs.

For a water resistant switch. snake leads through a tiny slit in a vacuum bag {stripped ends of wire are to be encapsulated with liquid rubber (RTV RUBBER GOO) allowed to cure before you do the bag part}. then you seal the hole with same goo, allow to cure. Put silica packet from pair of shoes whatever in bag, evacuate bag and seal with heat. Your switch is now in a vacuumed bag and is safe from moisture and simple spills and moisture

It is important to seal the wires to the insulator on the leads inside the bag, cause if you do not then it will draw air however slowly through the space betwixt the insulatied coating and the copper core.

use a copper PC etching board, no need to make circles solder the leads right to the board (best connection) put tiny bead of rubber goo around the board to connect them. If you wish to make it more sensative drill a tiny hole and make a valve seal and evacute enough to pull board together, but not touch. back up that simple valve with foil patch and rubber cement.

It doesn't take much force to connect, depending where you press on the disc. A person with some weakness (like with muscular dystrophy or ALS) might be able to use it.

I haven't tried hitting one with a drumstick or a mallet, but it would probably work.

If you want to change the amount of force needed, change the "buffer" material that holds the discs apart. If the velcro is too much, try gluing in some soft cloth, a few piece of a sponge, or whatever you have on hand. I find that foam mounting squares work well ( http://goo.gl/yfupg ).

In steps 2-4, I would do things a little differently my self. Instead of cutting out Circles and trying to then match them back to the CD's most likely ending up with miss matched pieces that are permanently stuck in place... If you've ever worked with Decals or Sticky Tape. You know how hard exact placement of something sticky and the object you want to stick it too can be! This should save you some time and frustration... I would just sit the CD's on the Sticky Foil to mark out squares slightly bigger than the CD's. Then cut out the Squares. Then, Peel the Backing off the Sticky Foil, with the Sticky Side up on your Work Bench - Table, what ever you have that it flat. Then just lay the CD's down on the Sticky Foil. Then flip them over and trim the Excess Foil with a Box Cutter or ExactO Knife, something with a thin sharp blade. Don't to this on your Wife or Mothers Kitchen Counter Top!:O She will whip your Butt if you do! And never let you forget how you completely ruined her Kitchen Counter Top! You've been warned!...;) You can use a flexible, straight edged plastic Squeegee to push the Air Bubbles out to the edge of the CD's, to get rid of them. Now a Days, I just use the ones that came in Some Auto Body Bondo that I bought a few years ago ( I keep them clean enough to reuse).They sell them all over for putting on Decals though. You can also use your fingers and thumb to Push the Air Bubbles to the Edges of the CD and eliminate them that way. An old trick for putting on Decals may help here. But, I'm not sure just how sticky the Sticky Foil is, since I've never actually worked with it. But, you may be able to use a wet sponge, dipped in water, squeezed out so that it does not drip, just leave it damp. Before you stick the CD's down on the Sticky Foil, just swipe them lightly withe the Wet Sponge. This will make it allot easier to wipe out the Air Bubbles after you stick them onto the Sticky Foil. I would just try one first and see how well this works, before doing them all this way... Ok, now you're ready to finish building your CD Switch and you didn't mess up any of your Foil and end up with stuck together forever pieces, good for nothing but the trash;)